1. Field of the Invention
The present invention relates to a mixer for mixing a pulse voltage and an electromagnetic wave, a matching device for achieving impedance matching of an electromagnetic wave output from the mixer, an ignition unit having the mixer, and a plasma generator having the ignition unit.
2. Related Art
As an alternative method of spark ignition of an internal-combustion engine or a plasma generation method, a technology of generating plasma by using spark discharge and electromagnetic wave radiation together is proposed. Compared with the case in which only an electromagnetic wave is used to generate the plasma, the technology may decrease required energy of the electromagnetic wave for generating the plasma. Patent Document 1 records a plasma generator, in which an antenna is configured near a discharge electrode of a spark plug. In addition, Patent Document 1 and Patent Document 2 record a spark plug configured with a transmission line and an antenna of an electromagnetic wave.
Patent Document 3 records a plasma generation device, which enables energy for discharging and energy of an electromagnetic wave to overlap on the same transmission line at a front section of a spark plug. Moreover, Patent Document 4 records a device, which is not a device for generating plasma, but combines a direct current (DC) voltage and microwave energy with a coaxial conductor, which are conducted into a combustion chamber to combine the microwave energy with a plasma mixture (a flame) in combustion.